What is my brother-in-law's wife to me?
It depends on which brother-in-law he is. If he's your spouse's brother, his wife is your co-sister-in-law — English has no everyday word, so that genealogical label (or just her name) is what you have. If he's your sister's husband, his wife is your sister — the very person who made him your brother-in-law.
Relationship
Co-sister-in-law
English has no single formal word for this relative — “co-sister-in-law” is the label genealogists use.
- You
- Your brother-in-law
- His wife
From the other side, you are their co-sibling-in-law.
This connection runs through a marriage, not a shared ancestor, so the ancestor chart can't draw it.
The calculator below works out blood relationships through a shared ancestor — use it to explore the rest of your tree.
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This relationship sits outside the shared-ancestor model, so the card above carries the answer and the calculator opens in its default state. Work out any blood relationship with it, or open the full relationship calculator.
FAQs
Is my brother-in-law's wife my sister-in-law?+
Not strictly. A sister-in-law is your spouse's sister or your sibling's wife; your spouse's brother's wife is your co-sister-in-law.
Who am I to my brother-in-law's wife?+
Her co-sibling-in-law — you each married into the same sibling group.
Does the calculator store my family details?+
No — it runs entirely in your browser. Nothing you enter is uploaded or saved on our servers.
Start with one relative and see what comes back.
Add what you remember and AncestorIQ searches for the rest. Free to build your tree for as long as you like.
No credit card needed. Your tree stays yours.
